Ferdaus ordered and acquired a $6,500 remote-controlled aircraft, an F-86 Sabre, that he kept in a rented storage facility.

Ferdaus was going to fly the RC aircraft using onboard GPS-guided autopilots, says the FBI. That's essentially the only difference between an enthusiast's cheap RC plane and a small drone: the autopilot allows manual control to be abandoned after take-off, allowing the aircraft to seek targets by GPS position alone. Autopilot electronics keep the plane flying straight and level through a series of GPS waypoints until the destination is reached.

He planned to have three remote-controlled planes (and load them with C4) and six people who would be armed with Kalashnikovs and grenades.